Peter Debruge Chief Film Critic As a critic, I’m always looking for a fresh challenge, which is one reason I took up writing about theater: It still has the capacity to scare me. I’ve reviewed nearly 1,700 movies in my time at Variety, but how to weigh in with authority on stage productions of William Shakespeare or Samuel Beckett when I haven’t seen most of their work performed, but know it only by reputation? Last year, I was nervous going in to a fresh revival of “Who’s Afraid of Virginia Woolf?” at Los Angeles’ Geffen Playhouse, as I had only the Mike Nichols movie as a reference point. How to judge Calista Flockhart’s performance, and what might I compare it to, not having seen Uta Hagen play Martha on Broadway? (I did manage to track down a vinyl recording of that show, but still…